World Bulletin / News Desk
In an interview with Anadolu Agency, one of the authors of the report, Firdaus Ali, a hydrologist from the University of Indonesia, has identified two main factors.
The first, he said, is the global warming phenomenon which has caused a rise in Java Sea and more frequent earthquakes. Besides that, overuse of groundwater and the massive and rapid development of high-rise buildings in the city has caused Jakarta to sink, little by little, he added.
"Unless a sea wall is built soon, Jakarta will be completely underwater," Firdaus said, adding the surface of the city was declining by 5 to 12 centimeters (almost 2 to 5 inches) per year.
According to the Dec. 21 report, coastal areas have sunk as much as 32 cm (12.5 inches) in recent years. Nearly 40 percent of Jakarta lies underwater, and most of the areas affected are in North Jakarta.
The situation has led to annual floods during the rainy season in Jakarta, the report said. Usually drained in hours, recently these floods take days to subside.
Firdaus called on the authorities to build an offshore wall around the city to combat its frequent water woes.
"The sea wall acts as a fortress against rising sea levels and can hold off the sinking process," he explained.
The central government in March began the construction of a sea wall in Muara Baru, North Jakarta, but the development faced issues when the dam broke and caused coastal flooding in nearby neighbourhoods.
An official at the Ministry of Maritime Affairs, Ridwan Djamaluddin, said the sinking was due to a combination of natural rock compaction and suctioning of groundwater.
Industries and developers, Ridwan said, are found to be repeat offenders when it comes to illegal digging of wells. "That is why the sea wall is being built, to reduce the effects of inundation."
The 4.5 kilometer-long (2.14-mile) sea wall project is divided across two locations in North Jakarta.
Muara Baru neighbourhood will have a 2.3 km (1.75 mi.) barrier protecting it from the sea and another 2.2 km (1.64 mi.) will be installed in Kalibaru neighbourhood.
So far, around 2.6 km (1.10 mi.) of the wall construction has been completed.